A 22-year-old man is fighting for life after he was allegedly assaulted in "unprovoked" attack outside a Melbourne nightclub on New Year's Day.
Police said a man and woman left a nightclub on Jackson Road in Toorak about 3am, before the man was allegedly set upon by the offenders.
He was taken to hospital with life-threatening injuries while the woman sustained minor injuries.
Victoria Police Assistant Commissioner Rick Nugent said the incident was "a tragic matter".
"We understand that the victim may have well been leaving his place of work and had just got back to his car when the (alleged) assault took place," he said.
"It's really sad and our thoughts are with his family at the moment."
The assistant commissioner said the attack put a dampener on what was a trouble-free night across the city.
The four offenders fled the scene on foot but were arrested nearby.
Three 19-year-old men from Dandenong and an 18-year-old Dandenong man are assisting police with their enquiries.